Aerating machine



INVENTOR':

ATTORNEY new Bees, 1939 1 UNITED STATES PATENT orrics mama momma HonelE.Booth, Salt Lake city. Utah Application November 11, 1931, Serial No.174,055 4 5 Claims. (01. 201-93) This invention relates to animprovement in aeration machines, and more particularly to an aerationor flotation machine oithe type forming the subject of my United StatesPatents Numbers 5 2,055,065 and 2,085,947, as well as oi an applica-,tion for United States patent, Serial No. 114,114, Henry F. Dietz,applicant.

Aeration or flotation machines embodying the inventions of the aforesaidpatents and appli m cation for patent, are peculiarly efilcient inproducing an abundant, finely bubbled froth, which is much desired inthe practice of modern flotation as applied-to metallurgical and otherpulps.

20 cal shaft and is submerged at-a low point, in a 7 mass of pulp.Compressed fluid, such as air, is conducted into the space enclosed bythe impeller,

and bubbles through the denture spaces. The

. initial bubbl'esare clipped into myriads of smaller I '25 bubbles bythe teeth andare projected outwardly into and through the pulp body.

Patent 2,085,947 is concerned with peeling the l bubbles emerging fromthe impeller, and guiding theseupwaniiythrough the pulp in an orderly 3omanner, this being accomplished by means ot'a plurality oi'rhladesspaced around the impeller.

Application Serial Number 114,114 is concerned with spacing the peelerblades apart from the bottom of the tank or other container consti- 5tuting the can or cells which confine the pulp, so

as toprovide circulation below the blades and thereby preventfthepocketing of the pulp'anda consequent deposition of coarse sands on .the'bottomofacell 1 'lhepresent is concerned with-theutilization to thefullest extent, of the advantages obtainable from the combined devicesoi! the aforesaid patents, and for its principal obiects:

, 45 First. To conserve the finely bubbled, mineralbearing froth in thefrothing compartment or zone, and to prevent its destruction and conse-'quent dropping-'01. mineral values because oi. coming .into contactwith the rotating impeller 50 shalt.

Second. Tocause the continuous, expeditious, and careful removal of thei'roth from the froth- :ing compartment or zoneby means of a stationarydeflector, without the use of paddles or other f moving elements;

1 would be of comparatively'larse size. However,"'| $5 Third. To providea simple, eflicient and inexpensive construction whereby the aforesaidobjects are accomplished.

.-In the drawing, which illustrates an excellent embodiment of theinvention: I

Fig. 1 is a plan of a flotation cell, partly in sec tion, taken on theline i-'-l in Fig. 2;

Fig. 2, avertical cross-section taken on the line 2-2 in Fig. 1; j

Fig. 3, a front elevation, partly in longitudinal, '10 vertical section,and drawn to'a reduced scale, of a battery of, for example, fourflotation cells operatively connected one to another in'series.

Referring to the drawing, the numeral 20 designates a tank or containeradapted to confine a '1 metallurgical flotation pulp in the form of abubble column 2| having the pulp level It.

Submersedat a low point in the bubble column is an impeller 26 which isfast on a shaft 27, this shaft being rotatably supported in a bearingstand 28. The stand in turn is S pported on'longitudinal beams 29, andthe beams may rest on end walls 30, and partition walls 3|, 3m, and lib,forming parts of the tank structure 20. Rte

shaft 21 may be provided with a pulley-(notl2 another and project fromthe basal rim-of the cone. A pipe 53, connected-with any suitable source0! compressed air or othergfluid' (not indi- 85 bated) may extendupwardly into the interior of the impeller. I I

Spaced apart radially from the-basal circumterence of the impeller, andpace apart'circumter'entially'trom'one another, is a plurality oi 40peler'blades 34,15 and It, the'bottom edges of which are spaced apartfrom the bottom 20a of tourcorners of the cell, where they restremovably on brackets a. I when compressed air is admitted through thevpipe I3, and the impeller is simultaneously retated at a suitableperipheral speed, for example,

1700 it. per minute, the airten'ds to bubble out through the spacesbetween the teeth or lugs 32. It the impeller were to standstill. thebubbles the properties of well known frothing reagents;

in rising through the pulp in the bubble column 2|, gather to themselvesthe mineral values in the pulp, and carry these values with them throughand upwardly from, the pulp surface 24.

Since the mineral extraction from flotation pulp is fractional in asingle cell, it is customary in practice to arrange the cells inbatteries, the

showing in Fig. 3 being typical. Communication .through the successive.cells may be effected by means of openings in the respective partitions,similar to the one indicated at 4|. Pulp may be fed to a battery througha feed inlet compartment 42 at the first cell, and be discharged from abattery over a weir consisting of removable sections 43 at the lastcell, the fiow of pulp being retarded by a baflle 45. By means of theremovable weir sections, the pulp level 24 in all the cells, may beregulated as desired.

What-has been explained so far, is a brief rsum of the disclosures inthe aforesaid patents and application for patent, and does notconstitute part of the present invention, excepting .in combination orconjunction with what is now to be described. Y

The tank and its component cells, in cross-section, are preferablysymmetrical on each side of the longitudinal axial plane of theimpeller, and

are arranged to discharge froth along the two opposing longitudinalsides of the cells. Bridging 4 the frothing compartment of each celllongitudinally, is a trough 46 which may have the inclined 55 dischargemouth may contain removable weir sec- 35 The opening 52; should beonly'large enough tosides46a, and the horizontal bottom 46'. The troughdips into the pulp so that the bottom of the trough is below the pulplevel 24. The trough divides the frothing compartment into two parts 25aand 25b, and the trough sides form deflectors, which at least partiallydefine the frothing compartments. Since the trough sides extend-upwardand forward in converging relation to the wall lines 41 of the cell,each frothing compartment is given the form of an inverted wedge; thefunction of which will presently be explained. Opposite eachdeflector46a is a. discharge mouth 5| through which the froth leaves the cell.Each tions 53, for the'purpose of varying, as may be required, the levelat which the froth overflows. .The trough may be supported by anysuitable means, for example, by clip angles 49 and 50,

go which are fastened 'to the opposing cross walls I level to whichfroth may rise, in order to prevent entry of froth into trough.

Inoperation, the abundance of fine bubbles produced by the impeller,riseth'rough the pulp, and emerge at the pulp level in a large volume offroth which brushes against the outside surfaces of the deflectors 46aand is positively and (5 continuously crowded ,or pushed throughthedischarge mouths. At the same time, the'trough prevents any portion ofthe froth from entering thereinto, and therefore, from coming intocontact with the rotating shaft 21.

In past practice I have found that. without the trough, froth piles uparound the shaft .21, and coming into close contact with the movingsurface of the shaft, 9. large part of the individual bubbles of thefroth are destroyed. Such destruction of bubbles," causes mineralparticles with which they were loaded, to be instantly dropped,

and to be drawn down along the shaft into the lower part of the bubblecolumn, where they must be picked up again by other bubbles. Obviously,such adverse action causes a veryv perceptible loss in efllciency, andcuts down the otherwise large.

capacity of the machine, correspondingly. The trough 46 not onlyprevents the objection just outlined, but at the same time, thestationary deflectors 46a, cause the froth from the frothingcompartments 25a and 25b, to be automatically pushed, positively andvigorously, over the weirs 53 instead of sluggishly building up in thespace pulps, for the reason, that it finds an extensive application inthis art. However, it is not necessarily restricted thereto, because thebridgingv trough with its upwardly diverging, deflecting side members,may be usefully employed inother arts where the aeration of a liquid orsemi-liquid is involved in order to produce a froth which rises throughthe mirror surface of the liquid. So also, the term aeration is notrestricted to ordinary air, but relates to any gaseous substance whichis to be diffused through a liquid or semiliquid.

. WhatIclaimis:

1. An aerating machine, comprising means defining a bubble column, ahollow, rotatable impellerhaving teeth extending outwardly from the rimthereof and being submerged at a low point in the bubble column, meansfor supplying compressed air to the interior of the impeller, peelerblades disposed around the impeller and spaced apart from one anotherand from the impeller, said peeler blades being adapted to guideupwardly; bubbles discharged by the impeller, and a trough bridging theupper part of the bubble column, the said trough including a lowerportion dipping below the level surface of the pulp in the bubble columnand sides inclined upwardly and outwardly from the said lower portionfor the. purpose of deflecting outwardly froth from the bubble column.

2. A flotation machine, including in combina tion, a cell structureenclosing a. bubble column, a hollow rotatable impeller having teethextend ing from the rim thereof, the said impeller being disposed at alow point in the bubble column,

means for supplying compressed air to the line peller, peeler bladesdisposed around the impeller and spaced apart from one another and fromthe impeller, the said peeler blades being disposed to guide upwardly,,bubbles discharged by the impeller, means defining a discharge mouth inproximity to the top of the bubble column, and a deflector defining atleast partially, an inverted 0 adapted to guide wedge-shaped frothingcompartment'immediatelv adjacent the said discharge mouth.

3. A flotation machine in accordance with claim 1, wherein a definitelevel surface oi pulp is maintained in the bubble column and the saiddeflector dips below the pulp level surface.

4. A fiotation machine, comprisinga container having longitudinal wallsand cross walls joined to the longitudinal walls and disposed to form acell for confining a bubble column of 9 119. a hollow rotatable impellerhaving teeth extending from the rim thereof and being submerged at a lowpoint in the bubble column, adriving shaft extending upward from theimpeller, means for PP impeller, peler blades disposed around and spacedradially apart from the impeller, the said peeler blades having theirlower edges spaced apart from the bottom surface of the container andbeing upwardly, bubbles discharged by the impeller and the -drivingshaft and compressed air-to the-interior of the at-the same time, topermit circulation of peeler blades and the bottom of the containenatrough bridgi umn from cross wall to cross wall, the said troughconsisting of a lower portion closely surronnding deflecting sideportions extending upwardly 'and outwardly from said least partiallydefine a frothing compartment immediately above the pulp surface level,

lower'portion' in order at Y and means defining froth discharge openingsin the said discharge openings being in cooperative proximity to therespective deflecting side portions of the saidtrougb.

5. A flotation machine as recited in claim 3,-in

wbichthe cell structure, the deflecting troughand thefrothingcompartment are each andall, symmetrical on both sides of thelongitudinal axial plane of the impeller and its driving shaft.

1.10mi; E...

the said longitudinal wens,

pulp in the space between the the upper part of the'bubble col-

